This invention relates to a bottom-supported vessel which is floated into position and then embedded in the seabed whereby the vessel is supported by the seabed while subaqueous operations are performed from the vessel.
Bottom-supported vessels from which subaqueous operations may be performed are disclosed in U.S. Letters Pat. Nos. 3,738,113 to Madary et al; 3,433,024 to Diamond et al; 3,021,680 to Hayward; 2,938,353 to Vorenkamp; 2,895,301 to Casagrande et al; and 2,622,404 to Rice. The aforementioned Hayward 3,021,680 and Diamond et al; 3,433,024 patents disclose a vessel including a submersible buoyant barge which is submerged to provide support for the work platform. In the aforementioned Vorenkamp, 29,622,353, Casagrande et al 2,895,301 and Rice 2,622,404 patents, the disclosed submersible barge is partially embedded into the ocean floor.
U.S. Letters Pat. No. 3,738,113 to Madary et al discloses an offshore drilling structure in which drilling operations are performed through a support leg extending from the drilling platform to the ocean floor.
U.S. Pat. No. 3,740,956 to Guy et al discloses a circular drilling structure which is floated into position, ballasted until it rests upon the ocean floor and filled with bulk material to create an artificial drilling island.
All of the offshore vessels disclosed in the aforementioned U.S. Letters Patents are, for one reason or another, somewhat disadvantageous for use in the shallow water, fast ice regions of the arctic seas.
The water depth in the fast ice region of the arctic seas is approximately 5 to 60 feet. To perform subaqueous operations in this region, a vessel preferably has a shallow draft. The ice thickness in the fast ice region of the artic seas is on the order of 7 feet. A vessel from which subaqueous operations will be performed in the fast ice region should be capable of remaining in an operating mode and withstanding the forces due to ice loads without assistance from other equipment to reduce its operating cost and maximize safety and reliability. Additionally, the vessel should be capable of setting its own required support foundation. Ice loads on the vessel and ice scouring effects should be kept to a minimum. Additionally, the vessel should be one that is readily movable from one position to another.
It is, therefore, an object of this invention to provide an improved bottom-supported vessel for performing subaqueous operations which has a minimal draft and which is capable of withstanding loads due to enroaching ice.
It is another object of this invention to provide an improved method for placing into operating position a vessel for performing subaqueous operations.
This and other objects and features of advantage of this invention will be apparent from the drawings, the written description of the preferred embodiment, and the appended claims.